The proposed project consists primarily of studies in vitro designed to elucidate further the endocrine regulation of gonadotropin receptors in ovarian cells. Based upon previous work in this laboratory, emphasis will focus upon: 1) definition of (endocrine) factors which will support induction/maintenance of gonadotropin receptors in moderate- or long-term granulosa cell monolayer culture in serum-containing and/or serum-free media; 2) the role of the ovarian theca interna in gonadotropin receptor regulation, specifically isolation of a thecal factor which neutralizes the inhibitory effects of serum upon FSH-dependent LH receptor induction; 3) inter-relationships between growth factors and classical endocrine regulators in induction/maintenance of gonadotropin receptors; 4) steroid and protein hormone inter-relationships in modulating cellular cAMP production in vitro. These studies should provide new information outlining specific mechanisms by which ovarian function is regulated at the level of the target cell.